Abstract

Background In vitro fermentation models have been used widely for
studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas
the suitability of these methods for enterolactone (ENL) formation has
received less attention. Aim The aim was to study the suitability of an in
vitro fermentation model for prediction of bioconversion of lignans to ENL, to
compare the approach with that of an in vivo rat model and to study the SCFA
formation in both models. Methods Predigested samples of rye bran (R),
flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal
control were incubated in an in vitro fermentation model using human faecal
microbiota. In the in vivo experiment rats consumed a non–fibre control diet
(C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone,
or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA
concentrations were measured from in vitro faecal fermentation samples and
from the intestinal contents of rats. Plasma ENL concentrations from rats were
also measured. Results The highest ENL production was found in vitro with
the F supplement (areas under curve: 740 ± 4, 7500 ± 400, 2600 ± 500 and 1520
± 70 nmol · h for the R, F, R&F supplements and faecal control, respectively).
In vivo, the concentration of ENL in caecal digesta from flaxseed meal was
significantly (P < 0.05) enhanced by the presence of rye bran (medians 261,
407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation
was found between the models regarding ENL production, possibly due to
different responses to the presence of rye bran matrix, differences in
microbiota or application of a batch in the in vitro fermentation model. Rye
bran supplementation enhanced butyrate production both in vitro and in vivo.
Conclusion In vitro fermentation and the in vivo rat models responded
differently to the presence of rye bran and no correlation with regard to the
ENL formation from flaxseed lignans was observed.

title = "Suitability of a batch in vitro fermentation model using human faecal microbiota for prediction of conversion of flaxseed lignans to enterolactone with reference to an in vivo rat model",

abstract = "Background In vitro fermentation models have been used widely for studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas the suitability of these methods for enterolactone (ENL) formation has received less attention. Aim The aim was to study the suitability of an in vitro fermentation model for prediction of bioconversion of lignans to ENL, to compare the approach with that of an in vivo rat model and to study the SCFA formation in both models. Methods Predigested samples of rye bran (R), flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal control were incubated in an in vitro fermentation model using human faecal microbiota. In the in vivo experiment rats consumed a non–fibre control diet (C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone, or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA concentrations were measured from in vitro faecal fermentation samples and from the intestinal contents of rats. Plasma ENL concentrations from rats were also measured. Results The highest ENL production was found in vitro with the F supplement (areas under curve: 740 ± 4, 7500 ± 400, 2600 ± 500 and 1520 ± 70 nmol · h for the R, F, R&F supplements and faecal control, respectively). In vivo, the concentration of ENL in caecal digesta from flaxseed meal was significantly (P < 0.05) enhanced by the presence of rye bran (medians 261, 407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation was found between the models regarding ENL production, possibly due to different responses to the presence of rye bran matrix, differences in microbiota or application of a batch in the in vitro fermentation model. Rye bran supplementation enhanced butyrate production both in vitro and in vivo. Conclusion In vitro fermentation and the in vivo rat models responded differently to the presence of rye bran and no correlation with regard to the ENL formation from flaxseed lignans was observed.",

T1 - Suitability of a batch in vitro fermentation model using human faecal microbiota for prediction of conversion of flaxseed lignans to enterolactone with reference to an in vivo rat model

AU - Aura, Anna-Marja

AU - Oikarinen, Seija

AU - Mutanen, Marja

AU - Heinonen, Satu-Maarit

AU - Adlercreutz, Herman

AU - Virtanen, Hannele

AU - Poutanen, Kaisa

PY - 2006

Y1 - 2006

N2 - Background In vitro fermentation models have been used widely for
studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas
the suitability of these methods for enterolactone (ENL) formation has
received less attention. Aim The aim was to study the suitability of an in
vitro fermentation model for prediction of bioconversion of lignans to ENL, to
compare the approach with that of an in vivo rat model and to study the SCFA
formation in both models. Methods Predigested samples of rye bran (R),
flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal
control were incubated in an in vitro fermentation model using human faecal
microbiota. In the in vivo experiment rats consumed a non–fibre control diet
(C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone,
or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA
concentrations were measured from in vitro faecal fermentation samples and
from the intestinal contents of rats. Plasma ENL concentrations from rats were
also measured. Results The highest ENL production was found in vitro with
the F supplement (areas under curve: 740 ± 4, 7500 ± 400, 2600 ± 500 and 1520
± 70 nmol · h for the R, F, R&F supplements and faecal control, respectively).
In vivo, the concentration of ENL in caecal digesta from flaxseed meal was
significantly (P < 0.05) enhanced by the presence of rye bran (medians 261,
407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation
was found between the models regarding ENL production, possibly due to
different responses to the presence of rye bran matrix, differences in
microbiota or application of a batch in the in vitro fermentation model. Rye
bran supplementation enhanced butyrate production both in vitro and in vivo.
Conclusion In vitro fermentation and the in vivo rat models responded
differently to the presence of rye bran and no correlation with regard to the
ENL formation from flaxseed lignans was observed.

AB - Background In vitro fermentation models have been used widely for
studies of shortchain fatty acid (SCFA) formation from carbohydrates, whereas
the suitability of these methods for enterolactone (ENL) formation has
received less attention. Aim The aim was to study the suitability of an in
vitro fermentation model for prediction of bioconversion of lignans to ENL, to
compare the approach with that of an in vivo rat model and to study the SCFA
formation in both models. Methods Predigested samples of rye bran (R),
flaxseed meal (F) alone, or in combination with rye bran (R&F) and a faecal
control were incubated in an in vitro fermentation model using human faecal
microbiota. In the in vivo experiment rats consumed a non–fibre control diet
(C) or diets supplemented either with rye bran (R), flaxseed meal (F) alone,
or with their combination (R&F) for four weeks. Enterodiol (END), ENL and SCFA
concentrations were measured from in vitro faecal fermentation samples and
from the intestinal contents of rats. Plasma ENL concentrations from rats were
also measured. Results The highest ENL production was found in vitro with
the F supplement (areas under curve: 740 ± 4, 7500 ± 400, 2600 ± 500 and 1520
± 70 nmol · h for the R, F, R&F supplements and faecal control, respectively).
In vivo, the concentration of ENL in caecal digesta from flaxseed meal was
significantly (P < 0.05) enhanced by the presence of rye bran (medians 261,
407 and 24 nmol/g in the F, R&F and C groups, respectively). No correlation
was found between the models regarding ENL production, possibly due to
different responses to the presence of rye bran matrix, differences in
microbiota or application of a batch in the in vitro fermentation model. Rye
bran supplementation enhanced butyrate production both in vitro and in vivo.
Conclusion In vitro fermentation and the in vivo rat models responded
differently to the presence of rye bran and no correlation with regard to the
ENL formation from flaxseed lignans was observed.